Key to long life could be flying overhead

Updated 11:27 am, Friday, May 17, 2013

Wisdom, even at age 62 or so (she's coy about her exact age), still has the lean, elegant figure she had in her 20s. She still moves gracefully, is as active as ever, and still likes to travel, logging around 50,000 air miles last year. Believe it or not, she even had a healthy baby this past February.

Sixty-two is an unheard of age for a woman to have a baby without fancy reproductive technology. But Wisdom is all natural. She is not a woman. She is an albatross, a 5-pound, island-hopping, squid-eating seabird with the wingspan of Michael Jordan. She is a feathered bundle of remarkable survival machinery.

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What is it about being able to fly that allows animals to live such a long time? To put Wisdom's longevity, reproductive and otherwise, in some context, remember that larger animal species typically live longer than smaller ones. Elephants live longer than horses, which live longer than dogs, which live longer than mice. An average mammal Wisdom's size never lives longer than a dozen years, even in the relatively pampered and protected life in a zoo. Yet here Wisdom is, still going strong in her 60s.

If you had to guess what sort of bird might live a long, long time, you might pick an albatross. They spend their lives far out at sea, touching down only on islands. So they avoid typical land-based dangers such as cats. They also have an incredibly energy-conserving mode of flight, using the wind-buffeting ocean waves to fly hour after hour without flapping their wings even once. A bird's heart rate while flying like this barely differs from when it is resting on the ground.

Practically all flying birds — even those considerably less laid back than Wisdom — live a long time. Take, for instance, the wonderfully named bristle-thighed curlew, a 11/2-pound wading bird with a ridiculously long, curved beak. It flies nonstop for more than a week during its 7,000-mile migration from Alaska to New Zealand. It makes this strenuous flight twice a year, must avoid diseases, bad weather and predators and still manages to survive into its 20s.

Even more amazing, a hummingbird weighing less than a dime and beating its wings 50 times per second as its heart pounds away faster than a machine gun can fire, flies nonstop across the Gulf of Mexico in the fall, makes the return trip in the spring, yet still lives up to a decade. That is three times as long as a mouse living a life of protected leisure in my laboratory.

Even those annoyingly noisy black birds — grackles — that haunt our power lines and parking lots by the thousands here in San Antonio in the fall and winter can live substantially longer than your dog.

Can we learn something about successful aging from the birds? Maybe so. Even when resting, birds consume about twice as much oxygen as do mammals like us. That oxygen plus the food they eat is used to produce energy. However, it also produces tissue-damaging oxygen free radicals.

Each cell in a bird consumes two to five times more oxygen over bird's lifetime than a person's cells do over a human lifetime, somehow avoiding catastrophic damage from these radicals. If we can figure out how they manage to survive this oxygen assault, maybe we can engineer or medicate our own cells to do the same. It may not make us capable of flying nonstop from Alaska to New Zealand, but it could lead to longer, healthier lives.